scholarly journals Microbial Electrochemical Oxidation of Anaerobic Digestion Effluent From Treating HTC Process Water

2021 ◽  
Vol 3 ◽  
Author(s):  
Shixiang Dai ◽  
Benjamin Korth ◽  
Carsten Vogt ◽  
Falk Harnisch
Keyword(s):  
Anaerobic Digestion ◽  
Oxygen Demand ◽  
Community Analysis ◽  
Hydrothermal Carbonization ◽  
Cod Removal ◽  
Microbial Community Analysis ◽  
Process Water ◽  
Material Synthesis ◽  
Current Production ◽  
High Chemical Oxygen Demand

Hydrothermal carbonization (HTC) is a promising technology for chemical and material synthesis. However, HTC produces not only valuable solid coal-materials but also yields process water (PW) with high chemical oxygen demand (COD) that requires extensive treatment. Anaerobic digestion (AD) has been used for initial treatment of HTC-PW, but the AD effluent is still high in COD and particles. Here, we show that microbial electrochemical technologies (MET) can be applied for COD removal from AD effluent of HTC-PW. Bioelectrochemical systems (BES) treating different shares of AD effluent from HTC-PW exhibited similar trends for current production. Thereby, maximum current densities of 0.24 mA cm−2 and COD removal of 65.4 ± 4.4% were reached (n = 3). Microbial community analysis showed that the genus Geobacter dominated anode biofilm and liquid phase of all reactors indicating its central role for COD oxidation and current generation.

scholarly journals Multiple Effects of Different Nickel Concentrations on the Stability of Anaerobic Digestion of Molasses

2021 ◽  
Vol 13 (9) ◽  
pp. 4971
Author(s):  
Sohail Khan ◽  
Fuzhi Lu ◽  
Muhammad Kashif ◽  
Peihong Shen
Keyword(s):  
Anaerobic Digestion ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Methane Content ◽  
Ion Concentration ◽  
Biogas Yield ◽  
Cod Removal Rate ◽  
The Stability ◽  
High Chemical Oxygen Demand

Molasses is a highly thick by-product produced after sugarcane crystallization constitutes large amounts of biodegradable organics. These organic compounds can be converted to renewable products through anaerobic digestion. Nevertheless, its anaerobic digestion is limited due to its high chemical oxygen demand (COD) and ion concentration. The effects of nickel (Ni2+) on the stability of anaerobic digestion of molasses were established by studying the degradation of organic matter (COD removal rate), biogas yield, methane content in the biogas, pH, and alkalinity. The results showed that there were no significant effects on the stability of pH and alkalinity. Increased COD removal rate and higher methane content was observed by 2–3% in the digesters receiving 2 and 4 mg/L of Ni2+ in the first phase of the experiment. Ni2+ supplemented to reactors at concentration 2 mg/L enhanced biogas yield. Overall, it is suggested that the addition of Ni2+ has some effects on the enhancement of biogas yield and methane contents but has no obvious effects on the long-lasting stability of the molasses digestion.

scholarly journals An electrode-assisted anaerobic digestion process for the production of high-quality biogas

2019 ◽  
Vol 79 (11) ◽  
pp. 2145-2155 ◽  
Author(s):  
K. Yanuka-Golub ◽  
K. Baransi-Karkaby ◽  
A. Szczupak ◽  
L. Reshef ◽  
J. Rishpon ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
High Efficiency ◽  
Community Analysis ◽  
Microbial Community Analysis ◽  
High Rate ◽  
Production Yield ◽  
Organic Load ◽  
Electrolysis Cell ◽  
Biogas Upgrading ◽  
Ch4 Production

Abstract Biogas is a sustainable, renewable energy source generated from organic waste degradation during anaerobic digestion (AD). AD is applied for treating different types of wastewater, mostly containing high organic load. However, AD practice is still limited due to the low quality of the produced biogas. Upgrading biogas to natural gas quality (>90% CH4) is essential for broad applications. Here, an innovative bio-electrochemically assisted AD process was developed, combining wastewater treatment and biogas upgrading. This process was based on a microbial electrolysis cell (MEC) that produced hydrogen from wastewater at a relatively high efficiency, followed by high-rate anaerobic systems for completing biodegradation of organic matter and an in situ bio-methanation process. Results showed that CH4 production yield was substantially improved upon coupling of the MEC with the AD system. Interestingly, CH4 production yield increase was most notable once circulation between AD and MEC was applied, while current density was not markedly affected by the circulation rates. The microbial community analysis confirmed that the MEC enhanced hydrogen production, leading to the enrichment of hydrogenotrophic methanogens. Thus, directing soluble hydrogen from the MEC to AD is plausible, and has great potential for biogas upgrading, avoiding the need for direct hydrogen harvesting.

scholarly journals Performance of Anaerobic Digestion of Acidified Palm Oil Mill Effluent under Various Organic Loading Rates and Temperatures

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2432
Author(s):  
Muhammad Arif Fikri Hamzah ◽  
Peer Mohamed Abdul ◽  
Safa Senan Mahmod ◽  
Azratul Madihah Azahar ◽  
Jamaliah Md. Jahim
Keyword(s):  
Anaerobic Digestion ◽  
Palm Oil ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Oxygen Demand ◽  
Microbial Community Analysis ◽  
Palm Oil Mill Effluent ◽  
Methane Formation ◽  
Organic Loading ◽  
Loading Rates ◽  
Palm Oil Mill

This study compared the performance of thermophilic and mesophilic digesters of an anaerobic digestion system from palm oil mill effluent (POME), in which temperature is a key parameter that can greatly affect the performance of anaerobic digestion. The digesters were incubated at two distinct temperatures of 55 and 37 °C, and operated with varying organic loading rates (OLRs) of 2.4, 3.2, and 4.0 g COD/L.d by altering the chemical oxygen demand (COD) of acidified POME during feeding. The results indicated that the performance of anaerobic digestion increased as the OLR increased from 2.4 to 4.0 g COD/L.d. At the OLR of 4.0 g COD/L.d, the thermophilic condition showed the highest methane yield of 0.31 ± 0.01 L/g COD, accompanied by the highest COD removal and volatile solid reduction, which were found to be higher than the mesophilic condition. Microbial community analysis via denaturing gradient gel electrophoresis (DGGE) revealed that Methanothermobacter sp. emerges as the dominant microbe, which is known to utilize the carbon dioxide pathway with hydrogen acting as an electron donor for methane formation

scholarly journals Simultaneous nitrification and denitrification (SND) bioaugmentation with Pseudomonas sp. HJ3 inoculated for enhancing phenol and nitrogen removal in coal gasification wastewater

2019 ◽  
Vol 80 (8) ◽  
pp. 1512-1523
Author(s):  
Weiwei Ma ◽  
Yuxing Han ◽  
Wencheng Ma ◽  
Hongjun Han ◽  
Chunyan Xu ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Coal Gasification ◽  
Oxygen Demand ◽  
Community Analysis ◽  
Microbial Community Analysis ◽  
Simultaneous Nitrification And Denitrification ◽  
Pseudomonas Sp ◽  
Coal Gasification Wastewater ◽  
Nitrification And Denitrification

Abstract A simultaneous nitrification and denitrification (SND) bioaugmention system with Pseudomonas sp. HJ3 inoculated was established to explore the potential of simultaneous phenol and nitrogen removal in coal gasification wastewater (CGW). When the concentration of influent chemical oxygen demand (COD) and total phenols (TPh) was 1,765.94 ± 27.43 mg/L and 289.55 ± 10.32 mg/L, the average removal efficiency of COD and TPh at the stable operating stage reached 64.07% ± 0.76% and 74.91% ± 0.33%, respectively. Meanwhile, the average removal efficiency of NH4+-N and total nitrogen (TN) reached 67.96% ± 0.17% and 57.95% ± 0.12%, respectively. The maximum SND efficiency reached 83.51%. Furthermore, SND bioaugmentation performed with good nitrification tolerance of phenol shock load and significantly reduced toxic inhibition of organisms. Additionally, the microbial community analysis indicated that Pseudomonas sp. HJ3 was the predominant bacterium in the SND bioaugmentation system. Moreover, the indigenous nitrogen removal bacteria such as Thauera, Acidovorax and Stenotrophomonas were enriched, which further enhanced the nitrogen removal in the SND bioaugmentation system. The results demonstrated the promising application of SND bioaugmentation for enhancing simultaneous phenol and nitrogen removal in CGW treatment.

scholarly journals Inhibition during Anaerobic Co-Digestion of Aqueous Pyrolysis Liquid from Wastewater Solids and Synthetic Primary Sludge

2020 ◽  
Vol 12 (8) ◽  
pp. 3441 ◽  
Author(s):  
Saba Seyedi ◽  
Kaushik Venkiteshwaran ◽  
Nicholas Benn ◽  
Daniel Zitomer
Keyword(s):  
Methane Production ◽  
Oxygen Demand ◽  
Community Analysis ◽  
Gas Production ◽  
Microbial Community Analysis ◽  
Pyrolysis Gas ◽  
Primary Sludge ◽  
Bio Oil ◽  
Concomitant Reduction ◽  
Pyrolysis Liquid

Pyrolysis can convert wastewater solids into useful byproducts such as pyrolysis gas (py-gas), bio-oil and biochar. However, pyrolysis also yields organic-rich aqueous pyrolysis liquid (APL), which presently has no beneficial use. Autocatalytic pyrolysis can beneficially increase py-gas production and eliminate bio-oil; however, APL is still generated. This study aimed to utilize APLs derived from conventional and autocatalytic wastewater solids pyrolysis as co-digestates to produce biomethane. Results showed that digester performance was not reduced when conventional APL was co-digested. Despite having a lower phenolics concentration, catalyzed APL inhibited methane production more than conventional APL and microbial community analysis revealed a concomitant reduction in acetoclastic Methanosaeta. Long-term (over 500-day) co-digestion of conventional APL with synthetic primary sludge was performed at different APL organic loading rates (OLRs). Acclimation resulted in a doubling of biomass tolerance to APL toxicity. However, at OLRs higher than 0.10 gCOD/Lr-d (COD = chemical oxygen demand, Lr = liter of reactor), methane production was inhibited. In conclusion, conventional APL COD was stoichiometrically converted to methane in quasi steady state, semi-continuous fed co-digesters at OLR ≤ 0.10 gCOD/Lr-d. Undetected organic compounds in the catalyzed APL ostensibly inhibited anaerobic digestion. Strategies such as use of specific acclimated inoculum, addition of biochar to the digester and pretreatment to remove toxicants may improve future APL digestion efforts.

scholarly journals Coupling hydrothermal carbonization with anaerobic digestion: an evaluation based on energy recovery and hydrochar utilization

2021 ◽  
Vol 8 (3) ◽  
pp. 1444-1453
Author(s):  
Mahmood Al Ramahi ◽  
Gábor Keszthelyi-Szabó ◽  
Sándor Beszédes
Keyword(s):  
Anaerobic Digestion ◽  
Energy Recovery ◽  
Oxygen Demand ◽  
Hydrothermal Carbonization ◽  
Steam Gasification ◽  
Post Treatment ◽  
Point Of View ◽  
Yield Potential ◽  
Treatment Technique ◽  
Dairy Sludge

This work evaluates the effect of hydrothermal carbonization (HTC) as a pretreatment and post-treatment technique to anaerobic digestion (AD) of dairy sludge. HTC's effect on AD was evaluated based on energy recovery, nutrient transformation, and hydrochar utilization. The first approach was executed by performing HTC under a range of temperatures before mesophilic AD. HTC optimal pretreatment temperature was 210 °C for 30 min residence time. HTC pretreatment significantly increased the methane yield potential by 192%, the chemical oxygen demand removal by 18%, and the sludge biodegradability during AD by 30%. On the other hand, the application of HTC after AD (post-treatment) increased the total energy production, i.e., in addition to methane, a hydrochar with a caloric value of 10.2 MJ/kg was also obtained. Moreover, HTC post-treatment improved the steam gasification performance of the AD digestate. From the fertilizer quality point of view, HTC implementation generally boosted the concentrations of macro, micro, and secondary nutrients, suggesting its suitability for use as a liquid fertilizer. Overall, the findings of the present study indicate that if bioenergy production were the main target, HTC post-treatment following AD would lead to the most promising outcomes.

scholarly journals Assessment of multiple anaerobic co-digestions and related microbial community of molasses with rice alcohol wastewater

2020 ◽  
Author(s):  
Sohail Khan ◽  
Fuzhi Lu ◽  
Qiong Jiang ◽  
Chengjian Jiang ◽  
Muhammad Kashif ◽  
...  
Keyword(s):  
Microbial Community ◽  
Biogas Production ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Ion Concentration ◽  
Microbial Community Analysis ◽  
Organic Loading Rate ◽  
Digestion Process ◽  
Archaeal Communities

Abstract Background Molasses is a highly dense and refined byproduct produced in the sugarcane industry, and it contains high amounts of degradable compounds. These compounds can potentially be converted into renewable products biologically. However, the involved biological process is negatively influenced by the high chemical oxygen demand (COD) of molasses and its high ion concentration, although this problem is commonly addressed by dilutions. Results The co-digestion of molasses with rice alcohol waste water (RAW) was compared with its mono-digestion at an increasing organic loading rate (OLR). Both processes were assessed by detecting the COD removal rate, the methane contents of biogas, and the structure and composition of microbial communities at different stages. Results showed that the co-digestion is stable up to a maximum OLR of 16 g COD L− 1d− 1. By contrast, after the acclimatization phase, the mono-digestion process was upset twice, which occurred at a maximum OLR of 9 and 10 g COD L− 1d− 1. The co-digestion procgess demonstrated consistency in terms of COD removal rates (86.36% ± 0.99–90.72% ± 0.63%) and methane contents (58.10% ± 1.12–64.47% ± 0.59%) compared with the mono-digestion process. Microbial community analysis showed that the relative abundance of bacterial and archaeal communities differs between the processes at different stages. However, in both processes, Propionibacteriaceae was the most abundant family in the bacterial communities, whereas Methanosaetaceae was abundant in the archaeal communities. Conclusion Rice alcohol wastewater could be a good co-substrate for anaerobic digestion of molasses. Integrate molasses into progressive biogas production at high OLR.

Edible Plant Oil Wastewater Treatment Using Electro-Fenton Technique: Experiment and Correlation

2018 ◽  
Vol 16 (8) ◽  
Author(s):  
Reza Davarnejad ◽  
Seyed Amir Mohajerani
Keyword(s):  
Reaction Time ◽  
Current Density ◽  
Oxygen Demand ◽  
Volume Ratio ◽  
Cod Removal ◽  
Interactive Effects ◽  
Molar Ratio ◽  
Plant Oil ◽  
Edible Plant ◽  
High Chemical Oxygen Demand

Abstract The edible plant oil production factories consume high amounts of water and contaminate the water resources. This type of wastewater consists of high chemical oxygen demand (COD) which should properly be treated by an efficient technique. Furthermore, it is containing some chemicals obtained from several sources such as H3PO4 (from hydration section), NaOH (from neutralization section) and citric acid (from nickel removal section). The conventional techniques cannot efficiently treat it which is full of COD. Therefore, the electro-Fenton process as a rapid, compact and efficient one has been encouraged to be applied. For this purpose, 47 experiments were designed and carried out using iron electrodes to evaluate the effects of five significant independent variables such as reaction time (min), pH, current density (mA/cm2), volume ratio of H2O2/wastewater (ml/l) and H2O2/Fe2+ molar ratio on the COD removal. Response surface methodology (RSM) was employed to assess individual and interactive effects of the parameters. The optimum conditions were experimentally obtained at reaction time of 87.33 min, pH of 3.03, current density of 57 mA/cm2, H2O2/wastewater volume ratio of 2.13 ml/l and H2O2/Fe2+ molar ratio of 3.61 for COD removal of 62.94 %.

Performance, Microbial Community Analysis and Fertilizer Value of Anaerobic Co-digestion of Cattle Manure with Waste Kitchen Oil

2019 ◽  
Vol 35 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Ricardo Galbiatti Sandoval Nogueira ◽  
Teng Teeh Lim ◽  
Haoqi Wang ◽  
Paulo Henrique Mazza Rodrigues
Keyword(s):  
Anaerobic Digestion ◽  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Preliminary Test ◽  
Community Analysis ◽  
Cattle Manure ◽  
Microbial Community Analysis ◽  
Fertilizer Value ◽  
Replication Control ◽  
Mesophilic Conditions

Abstract. Co-digestion trials of beef cattle manure and waste kitchen oil (WKO) were conducted to evaluate potential increase of biogas production for a local beef farm anaerobic digester. The trials were conducted using laboratory-scale, semi-continuously loaded digesters under mesophilic conditions, with 21-day hydraulic retention time (HRT). In a preliminary test, WKO was added at 0%, 0.5%, 1.0%, 1.5%, and 2.0% by volume, each with replicate digesters (n=2), except for the 0% level, which had one digester (n=1). Methane (CH4) yield per week increased linearly with WKO levels. Populations of bacteriodetes decreased, while clostridiales and synergistales increased with the WKO levels. A second test was conducted using treatments with more replication: control (n=3), and 1.0% (n=3) and 2% (n=3) WKO levels. Methane yields of the 1.0% and 2.0% WKO levels were 79.1% and 203% higher than the control, respectively. Addition of WKO have resulted in changes of the metagenomics of the digesters. Populations of clostridiales increased, while bacteroidales and euryarchaeota methanomicrobia YC-E6 decreased with the WKO levels. The findings confirm adding low amounts (1% and 2%) of WKO as co-digestion feedstock can be an effective way to increase CH4 yield for beef operation anaerobic digestion, especially when there are available feedstock nearby. Keywords: Anaerobic digestion, Biogas, Methane, Semi-continuous digesters.

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